Microcrystalline transparent copolyamide moulding compounds and use thereof for spectacle frames, glass for instruments and also covers and lamp covers are known for example from DE 43 10 970 A1. The polyamides described there are produced from 4,4′-diaminocyclohexylmethane as diamine component and dodecanoic acid as acid component.
In EP 1 595 907 A1, transparent amorphous polyamides which are based on diamines and a C14-dicarboxylic acid are furthermore described.
In addition, transparent, amorphous polyamides which have inter alia excellent stress-cracking resistance in most solvents are known from EP 0 725 101 A1.
With respect to scratch-resistance, the previously mentioned types of polymer are however disadvantageous. In order to solve this problem, EP 2 093 255 A2 proposes equipping transparent polyamides to be scratch-resistant by means of special additives.
WO 2008/025703 A1 describes copolyamide moulding compounds as coating of polycarbonate. Consequently, objects which are stress-cracking-insensitive, scratch-resistant and abrasion-resistant are made possible. The polyamides are described in more detail from page 2, line 6, it not being disclosed whether the mentioned polyamides concern transparent or opaque polyamides.
It has now been shown that the already known transparent copolyamide moulding compounds do have however disadvantages. It has emerged in particular that the scratch-resistance of the moulded articles produced from the transparent copolyamide moulding compounds is not always satisfactory. The copolyamide moulding compound should have as high a scratch-resistance as possible in order to ensure in particular a long lifespan and sustained transparency of the moulded articles produced herefrom. It is thereby essential that also the mechanical properties of the produced moulded articles are high, above all the toughness, e.g. described by the notch impact strength, the breaking elongation and/or the impact strength. Furthermore, it is essential for the transparent moulded articles that they have as high a transparency as possible. The copolyamide moulding compounds known to date have not corresponded to these requirements in their entirety.